Support for conversational data collections

[atliSig]

We would like to be able to capture conversational data via LOBE. This would require at least:

A new dataset db model specifically for conversational datasets
A new / or extended recording view for conversational collection. We should display at least feedback from mic and duration of recording in this view.

The biggest concern here are:

• Data integrity: we want to make sure that if an exception or any errors pop up that we loose only a limited amount of data. This requires some type of check-pointing or streaming to server.
• Memory overhead on client: Using some features in LOBE for an extended period of time might cause some memory overhead on client. We should investigate possible overheads and address them.

[judyfong]

If someone could combine samromur-chat into this repo that would be great https://github.com/cadia-lvl/samromur-chat